Congenital syphilis is a terrible disease. When syphilis goes untreated during pregnancy, miscarriages are incredibly common. And 40 percent of fetuses with syphilis that are carried to term are stillborn or die shortly after birth. Those who survive can suffer from deformed bones, anemia, enlarged livers and spleens, jaundice, meningitis, rashes, blindness, deafness, and other brain and nerve-related problems. 2016 saw 628 cases of congenital syphilis in the U.S., up from 492 in 2015.